In recent years, since miniaturization of electron devices, such as a transistor, progresses, and the size thereof has nano size, a new phenomenon called a quantum effect has been observed. Then, the development which aimed at achieving of ultra high-speed devices or new functional devices is advanced using such a quantum effect. In such environment, trials to perform large capacity communication, information processing, or imaging or measurement, etc. has been performed using the frequency region which is in particular called a THz band and of which frequency is from 0.1 THz (1011 Hz) to 10 THz. This frequency domain is undeveloped frequency region between light and electromagnetic waves, and if the device which operates with this frequency band is achieved, being used for many uses, such as measurement in various fields, such as physical characteristics, astronomy, living things, etc. the imaging, the large capacity communication and the information processing mentioned above, is expected.
As THz devices for oscillating high frequency electromagnetic waves of a THz frequency band, there have been known devices having a structure in which a Resonant Tunneling Diode (RTD) and a minute slot antenna is integrated, for example.
Moreover, there has been also disclosed a THz wave radiating apparatus comprising: a cap configured to cover a THz device; and a waveguide connected to the aforementioned cap.